<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>布局方案</title>
    <link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet">
    <style>
        .row div {
            height: 300px;
            border: 1px dashed #123;
        }
        
        .row .col-md-6 {
            margin-top: 20px;
            background-color: #dfdfdf;
        }
        
        .row .col-md-6:last-child {
            background-color: green;
        }
    </style>
</head>

<body>
    <div class="container">
        <div class="row">
            <div class="col-md-2">a</div>
            <div class="col-md-10">b
                <div class="row">
                    <div class="col-md-6">c</div>
                    <div class="col-md-6">d</div>
                </div>
            </div>
        </div>
    </div>
</body>

</html>